This description relates to reverse link power control in wireless networks.
Capacity of a wireless communication system may represent data throughput that can be supported by the system. Capacity can be an important factor for cellular service providers, because it directly impacts revenue. Code-Division Multiple Access (CDMA) wireless communications systems offer improved capacity and reliable communications for cellular and PCS systems.
In a CDMA system, each access terminal (AT) transmit signal utilizes a different pseudo random sequence signal that appears as noise to other ATs. This enables many ATs to transmit on the same frequency. However, each AT's transmitted signal contributes to interference in the transmitted signal of all other users. Thus, the total number of users supported by the system is limited by interference. Therefore, reducing the amount of interference in a CDMA wireless communications system increases capacity.
A typical problem in a CDMA cellular environment is the near/far problem. This entails the scenario where the transmit power of an AT near a radio node (RN) or a base station may drown out an AT which is far from the RN. This is effectively mitigated by controlling the transmit power of each AT via a power control scheme implemented by the access network (AN). AN continuously commands each AT to increase or decrease its transmit power to keep them all transmitting at the minimal power required to achieved the configured error rate for the operating data rate and maintain an overall balance of power while reducing the interference in the area of coverage.
In a CDMA 1x-EV-DO system (see e.g., CDMA2000 High Data Rate Packet Data Air Interface Specification, 3GPP2 C.S0024, Version 4.0, Oct. 25, 2002), the reverse link operates in CDMA and hence reverse link power control is needed.